Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education)/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
J Hazard Mater. 2022 May 5;429:128361. doi: 10.1016/j.jhazmat.2022.128361. Epub 2022 Jan 26.
Two-dimensional transition metal dichalcogenide (TMDC) nanomaterials have attracted tremendous research interest in various fields, but the effects of eco-corona formation on the transformation mechanisms and ecological risk of TMDCs remain largely unknown. The effect of eco-corona formation on TMDC reactivity was explored using extracellular polymeric substances (EPS) as the eco-corona constituents and single-layer molybdenum disulfide (SLMoS) as the model TMDC. We found that EPS promoted lattice distortion and the formation of defects (sulfur vacancies and pores) on SLMoS after it was aged (precoated) with EPS under simulated visible-light irradiation. In addition, the EPS-corona induced higher free radical (especially hyperoxide radical) photogeneration by SLMoS. Furthermore, compared to pristine SLMoS, SLMoS-EPS exhibited stronger developmental inhibition, oxidative stress, membrane damage, photosynthetic toxicity and metabolic perturbation effects on Chlorella vulgaris. However, the endocytosis pathway (especially macropinocytosis) of SLMoS entry into C. vulgaris was inhibited by EPS. Metabolic and transcriptomic analyses revealed that the enhanced toxicity of SLMoS-EPS was associated with the downregulation of fatty acid metabolism and transcription related to photosynthesis, respectively. The present work provides mechanistic insights into the roles of the EPS-corona on the environmental transformation and phytotoxicity of TMDCs, which benefit environmental safety assessments and sustainable applications of engineered nanomaterials.
二维过渡金属二硫属化物 (TMDC) 纳米材料在各个领域引起了极大的研究兴趣，但生态冠形成对 TMDC 转化机制和生态风险的影响在很大程度上仍不清楚。本研究采用细胞外聚合物 (EPS) 作为生态冠组成部分，单层二硫化钼 (SLMoS) 作为模型 TMDC，探讨了生态冠形成对 TMDC 反应性的影响。结果发现，在模拟可见光照射下，EPS 预涂覆 SLMoS 后，EPS 促进了 SLMoS 的晶格变形和缺陷（硫空位和孔隙）的形成。此外，EPS 冠诱导 SLMoS 产生更高的自由基（特别是超氧自由基）。与原始 SLMoS 相比，SLMoS-EPS 对小球藻表现出更强的发育抑制、氧化应激、膜损伤、光合作用毒性和代谢扰动作用。然而，EPS 抑制了 SLMoS 通过内吞作用进入 C. vulgaris。代谢组学和转录组学分析表明，SLMoS-EPS 增强的毒性与脂肪酸代谢下调和与光合作用相关的转录下调有关。本研究工作为 EPS 冠在 TMDC 环境转化和植物毒性中的作用提供了机制见解，有利于环境安全评估和工程纳米材料的可持续应用。
